What is the domain and range of #y=log_2x#?

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Answer 1 · 2017-07-31T12:18:03

Domain: #(0,oo)#

Range: #RR#

First, remember that you cannot take #log(0)# and you cannot take the logarithm of a negative number and get a real number

So, #x>0 => x in (0,oo)# which is our domain

Also, by the definition of #log_2x#

#y=log_2x#

#<=>#

#2^y=x#

which is defined for all real numbers #(RR)# , which gives us our range